Technical Field
The present application relates to a manufacturing method for a cylinder head, and more particularly, to the manufacturing method for a cylinder head with a surface on which a heat shield film (a heat insulation film) is formed.
Background Art
A combustion chamber of an engine is generally defined as surrounded space by a boa surface of a cylinder block, a top surface of a piston stored inside the bore surface, a bottom surface of a cylinder head, a bottom surface of an umbrella part of an intake valve which is disposed at an intake port formed in the cylinder head, and bottom surface of an umbrella part of an exhaust valve which is disposed at an exhaust port formed in the cylinder head.
In such a combustion chamber, a heat shield film may be formed on the top face of the piston and the like that constitute walls of the combustion chamber in order to reduce a cooling loss within an engine. For example, JP2012-156059A discloses an art in which an anode oxidation film (specifically an alumite film) is formed as a heat shield film on a bottom surface of a cylinder head that constitute walls of a combustion chamber of a spark ignition type engine. The publication mentioned above also discloses that the bottom surface has holes corresponding to an intake port, an exhaust port and a spark plug, which are preferably masked during anodizing treatment of the bottom surface.